coming out of 4w low in reverse

[dme100]

98 Ranger, 140k miles. I modified the hubs to manual control, following the directions here on TRS. That works good.
I plow with this truck, and lately, it comes out of 4wl when I put it in reverse, so I then have to shift into neutral, switch it out of 4w to 2w, then back to 4wl and then it works again.
Any ideas?
Thanks, David

 

[clevjake]

Do you have a manual transfer case or a switch to put you in 4x4?

 

[dme100]

4wd reverse issues

not a manual, switch type. when it comes out of 4wl, I put the brake on, shift (auto trans) into neutral, switch the 4w off then back on and it works for a while.